Type M2 macrophages secrete CC chemokine ligand 17 [chemokine (c-c motif) ligand 17, CCL17], CCL22, CCL24, etc. With low expression of IL-12 and high expression of IL-10, its tumor-killing activity is low, and TAM is closer to the functional phenotype of M2 macrophages [9, 10]. This evidence concerns the gene CCL17 and neoplasm.